Steve Jared McGarrett is a ranking lieutenant commander of the Navy SEALs. His superiors and commanding officers describe him as "the best they've ever seen". Steve is highly intelligent and intellectual which proves him to be a prime candidate to be the leader of the Five-0 task force.
Danny Williams - Steve and Danny have a love-hate relationship. In the earlier episodes, Danny frequently argues with Steve's method of "police work". Danny likes to speak his mind a lot with Steve, and much to Steve's annoyance, Danny is the perfect partner and in the later episodes, proves to be a great friend.
Chin Ho - Chin Ho and Steve have a very "normal" relationship with one another. They are seen getting along quite well most of the time. Chin Ho will always do what was asked by Steve and does it without any fuss. Chin Ho and Steve's great relationship comes from the bonding that Chin and Steve's father had shared which had passed on to his son, Steve.
Kono Kalakaua - Kono and Steve have a very professional relationship. They both seem to respect eachother as one in the team. Steve is never one to question Kono's abilities and trusts her to do the tasks that he has assigned for her.